Methods and Apparatuses for Manufacture of Smoking Article Filters

ABSTRACT

An apparatus for manufacturing a filter rod for a cigarette or other smoking article having a pattern formed in relief on the outer surface thereof. The apparatus comprises a passage including a portion configured to receive and compress filter material to form a filter rod and a belt extending along the passage to convey filter material through the passage. The apparatus includes a patterned relief surface configured to impress a relief pattern on a surface of a filter rod as it is formed within the passage.

The present invention relates to a method and apparatus for producingfilters and filter rods for use in the manufacture of smoking articles.

Filter materials are formed into rods during manufacture and such rodsmay be cut into smaller units for the application of filter tips tosmoking articles. Existing methods and apparatuses of producing filterrods can produce filter rods with relief patterns, such as grooves, ontheir outer surface and include forming a filter rod and subsequentlyforming a pattern/grooves into the outer surface of the filter rod usinga post-processing technique. An alternative existing method of formingfilter rods with a relief pattern in their outer surface includescreating the desired pattern in a plug wrap and then wrapping the filtermaterial in the shaped plug wrap so that the filter material conforms tothe applied shape of the outer plug wrap. In all cases, the filter rodsare formed using existing an method and apparatus, and the patternedshape for the filter is performed in a separate earlier or later step.

In accordance with various embodiments of the invention, there isprovided an apparatus for manufacturing a filter rod for a cigarette orother smoking article having a pattern formed in relief on the outersurface thereof, the apparatus comprising, a passage including a portionconfigured to receive and compress filter material to form a filter rodand a belt extending along the passage to convey filter material throughthe passage, wherein the apparatus includes a patterned relief surfaceconfigured to impress the relief pattern on a surface of a filter rod asit is formed within the passage.

The relief surface may be formed on the belt such that the belt engagesthe filter material and impresses the relief pattern on the surface ofthe filter rod as it passes through the passage. The belt may comprise aplurality of plates hingedly coupled end-to-end, and at least one of theplates may be metallic. Furthermore, at least one of the plates mayinclude a wear-resistant and/or non-stick coating.

The front and rear edges of each plate which are hingedly coupled to theadjacent plates, may be formed with a corresponding tessellating and/orsaw-tooth configuration. The hinged connection between the plates maycomprise a flexible cord or a plurality of hinge pins.

The belt may comprise a plurality of plates having respective patternedrelief surfaces which are spaced intermittently between plates without apatterned relief surface such that the resulting filter rod includes animpressed relief pattern on its outer surface at spaced intervals alongits length.

The belt may be driven over a plurality of guide rollers, wherein atleast one of the guide rollers may have a faceted outer surface and thebelt may be in registration with the at least one guide roller such thatthe plates of the endless belt lie flat on a facet of the at least oneguide roller as the belt passes over said guide roller.

The facets of the at least one guide roller may include a surface reliefpattern corresponding to the patterned relief surface of the plates ofthe belt such that the patterned relief surface of the plates of thebelt cooperate with the surface relief pattern on the facets of the atleast one guide roller as the belt passes over said guide roller.

The belt may comprise a flexible band with a layer of resilient materialformed thereon, and the patterned relief surface may be provided in theresilient material layer. The resilient material layer may be made of atleast one of rubber or plastic.

In an alternative embodiment, the relief surface may be formed on aninner surface of the passage such that the filter material engages therelief surface and the relief pattern is impressed into the filter rodas the filter rod passes through the passage. Such relief surface maycomprise one or more projections on an inner wall of the passage. Suchprojection(s) may be elongate rib(s) extending substantiallylongitudinally along at least part of the length of the passage.Alternatively, the or each projection may comprise nodes on an innerwall of the passage, for example, convex, pointed, pyramidal, square orfrusto-conical/pyramidal protrusions.

The passage may be configured to heat the filter tow material as ispasses therethrough. For example, the passage may include at least oneinlet tube to allow steam to be introduced into the interior of thepassage. Such inlet tube(s) may be formed in the side wall of thepassage between distal first and second ends thereof. Alternatively, orin addition, the passage may include one or more heating elements formedintegrally with the passage or provided on the passage. Such heatingelement(s) may comprise electrical heating element(s).

The passage may comprise a double wall structure along at least part ofits length. The double wall structure may comprise an outer wall and aninner wall spaced from the outer wall to define a cavity therebetween.The inner wall may be perforated. The outer wall may include at leastone inlet tube to allow steam to be introduced into the cavity betweenthe outer and inner walls and, in an embodiment where the inner wall isperforated, to allow steam into interior of the passage. Alternatively,the inner wall may omit any perforations.

The apparatus may be configured such that the belt is formed into atolled up state as it passes through the passage, such that the lateraledges of the belt are disposed proximate each other. The belt edges maybe close to but spaced from each other, in abutment, or may overlap eachother in said rolled up configuration of the belt. The passage mayinclude a pressing member configured to impart an inward pressing forceon the belt and/or filter rod as the filter rod is formed in thepassage. Such a member may comprise a mechanism, which may include asprung arm, and/or a roller biased inwardly towards the centre of thepassage. The member/mechanism may be formed on in inside wall of thepassage and may be provided at the top centre of the passage.

The belt or the passage may include a patterned relief surfaceconfigured to impress a grooved pattern on the outer surface of thefilter rod as it is formed in the passage.

Also provided is a method of manufacturing a filter rod for a cigaretteor other smoking article using a filter rod manufacturing apparatus asdefined above wherein the passage includes a first open end forintroduction of filter material and a second open end for expulsion of aformed filter rod, the passage narrowing between the first end and thesecond end so that as filter material is conveyed through the passage,it is compressed to form a filter rod, the method comprising feedingloose filter tow material onto the belt, conveying the filter towmaterial on the belt through the passage from the first open end to thesecond open end and thereby compressing the filter tow material to forma filter rod, and impressing a relief pattern on a surface of the filterrod as it passes through the passage.

The relief surface may be formed on the belt, and the method may furthercomprise the relief pattern being impressed on the surface of the filterrod by the patterned relief surface of the belt.

Alternatively, an inner surface of the passage may include the reliefsurface, and the method may further comprise the relief pattern beingimpressed on the surface of the filter rod by the patterned reliefsurface on in the inner surface of the passage.

The method may comprise feeding a plug wrap onto the belt and feedingthe loose filter tow material onto the plug wrap, such that the formedfilter rod is circumscribed by the plug wrap and the impressed reliefpattern is formed on the filter rod through the plug wrap.Alternatively, the method may comprise circumscribing a plug wrap aroundthe formed filter rod after it has exited from the passage. Yet further,the method may comprise feeding the filter tow material directly ontothe belt such that the impressed pattern in the resulting filter rod isformed directly on the filter tow material without any plug wrap aroundthe outer surface thereof.

A plasticiser may be entrained with the filter tow material, and themethod may further comprise introducing heat and/or steam to the passagein order to activate and/or accelerate the reaction of the plasticiserwith the filter tow material. The plasticiser may be entrained with thefilter tow material in a ratio of at least 8% by weight to dry weight offilter tow material, and may be between 8-18%, and may be between12-18%.

Embodiments of the invention are shown, by way of example only, in FIGS.2 to 14 of the accompanying drawings, in which:

FIG. 1 shows an existing filter rod forming apparatus;

FIG. 2 shows a filter rod forming apparatus according to a firstembodiment of the invention;

FIG. 3 shows an enlarged view of a section of the garniture belt of theapparatus of FIG. 2;

FIG. 4 shows a cross-section of the garniture belt of the apparatus ofFIG. 2, in a rolled-up state;

FIG. 5 shows an enlarged view of a section of garniture belt of a filterrod forming apparatus according to a second embodiment of the invention;

FIG. 6 shows an enlarged view of a section of garniture belt of a filterrod forming apparatus according to a third embodiment of the invention;

FIG. 7 shows an enlarged view of a section of garniture belt of a filterrod forming apparatus according to a fourth embodiment of the invention;

FIG. 8 shows a filter rod forming apparatus according to a fifthembodiment of the invention;

FIG. 9A shows a cross-sectional view of the apparatus of FIG. 8 alongthe line X-X;

FIG. 9B shows a cross-sectional view of the apparatus of FIG. 8 alongthe line Y-Y;

FIG. 10 shows a filter rod forming apparatus according to a sixthembodiment of the invention;

FIG. 11 shows a filter rod forming apparatus according to a seventhembodiment of the invention;

FIG. 12 shows a cross-sectional view of the apparatus of FIG. 11 alongthe line Z-Z;

FIG. 13 shows a filter rod forming apparatus according to an eighthembodiment of the invention; and

FIG. 14 shows a cross-sectional view of the apparatus of FIG. 13 alongthe line W-W;

Referring now to FIG. 1, an existing apparatus 10 for producing a filterrod is shown and comprises a ‘garniture’ 11 and a guide funnel 12. Thegarniture 11 is a passage in the form of a duct or tube, having a wideentrance opening 11 a and a narrow exit opening 11 b. The garniture 11narrows between the wide entrance opening 11 a and the narrow exitopening 11 b at a ‘tow guide’ portion 11 c. The rear section 11 d of thegarniture 11 between the tow guide 11 c and the narrow exit opening 11 bis substantially constant in cross-section along its length (as shown inFIG. 1), but in some apparatuses may continue to taper but more gentlythan the tow guide section 11 c. The tow guide section 11 c transitionsto the rear section 11 d at a portion known as a ‘tongue’. The tonguemay include a section of reduced taper than the tow guide portion. Thegarniture 11 is generally circular in cross-section. A continuous‘garniture belt’ 13 extends through the garniture 11 and over aplurality of guide rollers 14 and is driven to be conveyed around therollers 14 in the direction shown by arrows ‘A’. A plug wrap ‘P’ may befed from a spool 15 onto the upper surface of the garniture belt 13 andis conveyed through the garniture 11 by the moving garniture belt 13. Asthe plug wrap P travels though the garniture 11, the shape of thetapered tow guide 11 c (and tongue) deforms the garniture belt 13 andplug wrap P thereon such that, in cross-section, the plug wrap P goesfrom being flat (as it is on the spool 15) when it enters the wideentrance opening 11 a of the garniture 11, to a closed circle as itleaves the narrow exit opening 11 b of the garniture 11, completelysurrounding the formed filter rod. As the plug wrap P is wrapped aroundthe filter material, the edges meet to form a seam at an upper portionof the garniture 11. This seam may then be glued (or the plug wrap maybe pre-glued where the seam is to be formed).

A section of the upper portion of the garniture 11 may comprise aheating bar (not shown) to heat and activate the glue at the seam of theplug wrap to adhere the plug wrap in place around the filter material.Such a heater bar may be curved and sit in a correspondingly shapedrecess in the garniture 11 to form a continuous outer wall thereof.Furthermore, in some existing apparatuses, hot melt glue is applied tothe plug wrap which needs to be cooled to set and adhere the seamtogether. In such cases, the heater bar would not be present and acooling bar may be provided instead.

In use, loose filter tow material (not shown), such as loose celluloseacetate fibre, is fed into the funnel 12 as shown by arrow ‘B’ and isguided into the tow guide 11 c of the garniture 11 by a ‘transport jet’of compressed air from a jet nozzle (not shown). The filter tow materialis conveyed through the tapering tow guide 11 c on the plug wrap P sothat the loose filter tow material is formed into a more compacted rodas it emerges from the distal narrow end 11 b. The transport jet andguide funnel 12 serve to guide the loose filter tow material into thewide entrance opening 11 a, and the transport jet provides a continuousblast of compressed air which gathers the loose filter tow material intoa lightly compressed state and propels the lightly compressed filter towmaterial into the garniture 11.

As the filter tow material travels through the garniture 11 and iscompressed, the plug wrap P is folded around the outside of thecompressed cylinder of filter tow material and glue is applied to theover-lapping seam and heated to activate the glue, such that when thefilter tow material exits though the narrow exit opening 11 b of thegarniture 11, the filter tow material is formed into a compressedcylindrical filter rod 16 enveloped by an outer plug wrap. This existingprocess produces filter rods with a smooth outer surface. If a reliefpattern such as grooves are to be formed in the filter rods, these musteither be formed in a separate second process requiring furthermachinery and production time/complexity, or the plug wrap P must firstbe shaped (e.g. crimped) prior to being fed into the garniture 11 sothat the filter tow material conforms to the shape of the plug wrap P,again, involving further machinery and production time/complexity.

A method and apparatus 110 according to a first embodiment of theinvention, for producing filter rods having a relief pattern on an outersurface thereof, is shown in FIGS. 2-4 and, as with the existingmethod/apparatus described above, comprises a guide duct or ‘garniture’111 having a wide entrance 111 a and narrower exit 111 b, and a guidefunnel 112, the features of which are the same and/or function similarlyas those described above in reference to FIG. 1. The apparatus 110 alsoincludes a continuous belt or ‘garniture belt’ 113 which extends over aplurality of guide rollers 114 and is driven to be conveyed around therollers 114 in the direction shown by arrows ‘C’ in FIG. 2. Also as withthe existing filter rod producing apparatus, plug wrap ‘P’ is fed from aspool 115 onto the upper surface of the garniture belt 113 which conveysit through the garniture 111 which deforms the garniture belt 113 andplug wrap P thereon such that, in cross-section, the plug wrap P goesfrom being flat (as it is on the spool 115) when it enters the wideentrance opening 111 a of the garniture 111, to a closed circle as itleaves the narrow exit opening 111 b of the garniture 111, completelysurrounding the formed filter rod.

The apparatus 110 of the first embodiment of the present inventiondiffers from the existing apparatus 10 described above in theconstruction of the garniture belt 113 and the form of the guide rollers114. In an existing apparatus 10, the garniture belt 13 is a continuousflexible belt of material such as canvas or other woven fibre. In theapparatus 110 of the first embodiment of the invention however, thegarniture belt 113 is formed of a plurality of plates 117 hingedlyconnected to each other end-to-end. The construction of the garniturebelt 113 can be seen more clearly in the enlarged portion of FIG. 2 andin FIG. 3, which shows the plates 117 are formed with a series ofparallel ridges 118 and saw-toothed front and rear edges 119, 120. Theplates 117 are connected together with saw-toothed front edge 119tessellating with the saw-tooth rear edge 120 of the preceding plate117, and a flexible connecting element 121 extending through aperturesformed transversely through the saw-tooth sections 119, 120. Theconnecting element can be a flexible thread such as, but not limited to,plastic thread, metal wire, or fabric thread.

In order for the plates 117 to pass through the garniture 111, theplates 117 are elastically deformable from their flat state (shown inFIG. 3) to a rolled-up state (see FIG. 4) in which they are rolled abouttheir longitudinal front/rear axis. In order for this deformation tooccur, the connecting element 121 may be flexible to also deform betweena straight configuration when the plates 117 are in their flat state toa curved configuration when the plates 117 are in their rolled-up state.

In order to minimise the stress on the plates 117 as they arecontinuously conveyed around the belt path of the garniture 111, therollers 114 do not have a rounded/continuously curved outer surface asin an existing apparatus 10, but instead may have a series of flat faces122 which are the same length as that of the plates 117. The garniturebelt 113 length, position and dimensions of the rollers 114 anddimensions of the flat faces 122 thereof are configured such that as thegarniture belt 113 passes over each roller 114, each plate 117 lies on aflat face 122 of the roller with the connecting element 121 aligned withthe edge formed between adjacent flat faces 122. Therefore, the plates117 are not forced to deform by curving about an axis transverse totheir front/rear direction, as they would if they were to pass overround-faced rollers.

In use, as with an existing filter-rod forming apparatus, loose filtertow material (not shown), such as cellulose acetate, is fed into thefunnel 112 as shown by arrow ‘D’ and is guided into the garniture 111 bya jet of compressed air from a jet nozzle (not shown). As the garniturebelt 113 enters and is conveyed through the garniture 111, the plates117 are deformed from their flat state to their rolled-up state shown inFIG. 4, and the filter tow material is conveyed through the taperedgarniture 111 on the plug wrap P. By the time the garniture belt 113reaches the narrow end 111 b of the garniture 111, the flat plates 117form a closed circle in cross-section, and the loose filter tow materialis formed into a compact rod 116 circumscribed by the plug wrap P.

As the filter tow material travels through the garniture 111, the ridges118 in the plates 117 impress a grooved pattern on the outer surface ofthe filter rod 116 so that when the filter rod 116 exits though thenarrow exit opening 111 b of the garniture 111, it has a series oflongitudinal grooves formed around the entire perimeter of its outersurface. In order for the grooved pattern to remain set in the filterrod, the garniture 111 includes a heating means which accelerates thereaction of a plasticiser that is mixed with the cellulose acetatefibres to set the fibres in the shape formed by the plates 117 so thatthe shape remains in the resulting filter rod 116 once it emerges fromthe narrow exit opening 111 b of the garniture 111. It will beappreciated that in the existing filter rod forming apparatus, it isless crucial that the filter shape is set so quickly—i.e. so that itsets when the filter rod 16 emerges from the garniture 11—since nopattern is formed in the surface of the filter rod which may be lost ifthe filter material is not set and is free to expand after exiting thegarniture 11.

In the first embodiment of the invention shown in FIG. 2, the heatingmeans comprises inlet ducts 124 along the length of the garniture 111through which steam can be injected, as shown by arrows CS′. In orderthat the heat of the steam can be most efficiently applied to thecellulose acetate and plasticiser mix, the garniture belt 113 ispreferably porous to allow steam therethrough. In the embodiment shown,the steam can pass through the garniture belt 113 at the gaps where theindividual plates 117 are joined. However, it is also intended withinthe scope of the invention that further means may be provided toincrease the porosity of the garniture belt, such as perforations formedin the plates 117 themselves.

The tapering of the garniture 111 from the wide open end 111 a to thenarrow exit end 111 b also creates an inward pressure on the filter towmaterial as it passes therethrough which squeezes it and also helps theshaped pattern remain impressed on the resulting filter rod 116. Inorder for the shape to more effectively be retained in the filter rod116, it may also be preferable for an increased amount of plasticiser tobe mixed with the cellulose acetate fibres than would be used inexisting rod manufacture. Around 4-8% of plasticiser by weight to dryweight of cellulose acetate tow may be used in existing processes,although in the filter rod manufacturing process of the invention,preferably an increased amount of plasticiser may be used, such asbetween 8-18% by weight to dry weight of cellulose acetate tow, andpreferably between 12-18% by weight to dry weight of cellulose acetatetow.

FIG. 5 shows an enlarged close up view of a garniture belt 213, similarto the view of FIG. 3, of an apparatus 210 of a second embodiment of thepresent invention. The apparatus 210 differs from the apparatus 110 ofthe first embodiment in the configuration of the garniture belt 213, andall remaining features are the same as described previously and retainthe same reference numerals. The garniture belt 213 comprises aplurality of linked plates 117 formed with a series of parallel ridges118 and saw-toothed front and rear edges 119, 120, and the plates 117are hingedly connected to each other end to end. However, unlike theapparatus 110 of the first-described embodiment, the plates 117 are notconnected by a single flexible connecting element 121 but instead aplurality of connecting pins 221 link adjacent plates 117, oneconnecting pin 221 on each angled face of the saw-tooth sections 119,120 connecting to the adjacent angled face of the saw-tooth section 119,120 of the adjacent plate 117. The connecting pins 221 can be metal orplastic pins. Such connecting pins 221 may comprise ball and socketjoints to allow flexibility of movement between individual pins.Alternatively, the pins 221 may include a pivot connector along theirlength between each plate to provide the garniture belt 213 with therequired flexibility.

Operation of the apparatus of the second embodiment of the invention isthe same as that described above for the first embodiment of theinvention such that a formed filter rod 116 exits though the narrow exitopening 111 b of the garniture 111 with a series of longitudinal groovesformed around the entire perimeter of its outer surface. However, inthis embodiment, as the garniture belt 213 passes through the garniture111 and the plates 117 are deformed from their flat configuration totheir rolled-up state, the joins between the plates 117 are allowed todeform due to the plurality of individual connecting pins 221 beingdiscrete items from one another, rather than the single connectingelement 121 being a flexible component, as in the first embodiment ofthe invention.

FIG. 6 shows an enlarged close up view of a garniture belt 313, similarto the view of FIGS. 3 and 5, of an apparatus 310 of a third embodimentof the present invention. The apparatus 310 differs from the apparatuses110, 210 of the first and second embodiments in the configuration of thegarniture belt 313, and all remaining features are the same as describedpreviously and retain the same reference numerals. Instead of comprisinga plurality of linked plates as with the first and second embodiments ofthe invention, the garniture belt 313 comprises a continuous flexiblebelt 317 a which has a flexible but resilient coating 317 b formed onone side thereof which has a series of parallel ridges 318 extending ina longitudinal direction of the garniture belt 313. The coating 317 bmay be of a suitable resilient but preferably heat-resistant materialsuch as plastic and/or rubber, and can be formed as a separate componentand subsequently bonded to the underlying flexible belt 317 a, or may bemoulded onto the flexible belt 317 a and set thereon with the desiredsurface relief pattern. The coating 317 b is sufficiently flexible toenable the garniture belt 313 to deform into a rolled up state, similarto that shown in FIG. 4. In addition to the above, as the garniture belt313 of the third embodiment of the invention is not made up of discreteplates joined together, the apparatus 310 may include existingcurved-face rollers 14 instead of flat faceted rollers 114 of the firstand second embodiments of the invention.

Operation of the apparatus 310 of the third embodiment of the inventionis the same as that described above for the first embodiment of theinvention such that a formed filter rod 116 exits though the narrow exitopening 111 b of the garniture 111 with a series of longitudinal groovesformed around the entire perimeter of its outer surface. However, it isthe ridges 318 in the resilient coating 317 b which form thegrooves/patterns in the filter rod as it passes through the garniture111.

FIG. 7 shows an enlarged close up view of a garniture belt 413, similarto the view of FIGS. 3, 5 and 6, of an apparatus 410 of a fourthembodiment of the present invention. Depending on the implementation,the apparatus 410 may be similar or identical to that of the thirdembodiment of the invention except that instead of the resilient coating317 b being provided along the entire length of the flexible belt 317 a,such a resilient coating 417 b with a surface relief pattern in the formof ridges 418 is provided intermittently along the flexible belt 417 a,such that a grooved/shaped pattern is only imparted onto the resultingfilter rod intermittently or in any desired spacing.

As with the third embodiment of the invention, the coating 417 b may beof a suitably resilient and preferably heat-resistant material such asrubber and/or plastic, and may be formed as a separate component andsubsequently bonded to the underlying flexible belt 417 a, or may bemoulded onto the flexible belt 417 a and set thereon with the desiredsurface relief pattern. Also, the coating 417 b is sufficiently flexibleto enable the garniture belt 413 to deform into a rolled up state,similar to that shown in FIG. 4, and the apparatus 410 may includeexisting curved-face rollers 14 instead of flat faceted rollers 114 ofthe first and second embodiments of the invention.

Operation of the apparatus 410 of the fourth embodiment of the inventionmay be similar to or the same as that described above for the thirdembodiment of the invention such that a formed filter rod 116 exitsthough the narrow exit opening 111 b of the garniture 111 with a seriesof longitudinal grooves formed around the entire perimeter of its outersurface. However, in some implementations, the grooved pattern is onlyimparted onto the resulting filter rod intermittently.

In all of the garniture belts 213, 313, 413 of the second to fourthembodiments of the invention, additional means may be provided toincrease the porosity of the garniture belts to improve the heattransfer of the steam to the cellulose acetate/plasticiser mix, such asperforations in the belt/plates.

A filter rod producing apparatus 510 of a fifth embodiment of theinvention is shown in FIGS. 8, 9A and 9B, which is similar to the firstembodiment shown in FIG. 2 and like features retain the same referencenumerals. However, the apparatus 510 of the fifth embodiment of theinvention has a differing configuration of the garniture 511. Morespecifically, the garniture 511 comprises a double-walled structure witha solid outer wall 511 a and a perforated inner wall 511 b, defining acavity 512 therebetween. This is shown more clearly in FIGS. 9A and 9Bwhich are cross-sectional views along the lines X-X and Y-Y of FIG. 8respectively. The garniture 511 includes inlet ducts 124 to allow steam‘S’ to be fed into the cavity 512 between the walls 511 a, 511 b of thegarniture 511. The steam is then able to fill the cavity 512 and fromthere pass through the perforations 513 in the inner wall 511 b to thegarniture belt 113 within the garniture 511. As discussed above, thegarniture belt 113 is preferably porous to as to allow the heat of thesteam to more effectively transfer to the cellulose acetate andentrained plasticiser to effect the accelerated reaction and setting ofthe filter rod 116.

It will be appreciated that an advantage of the apparatus 510 of thefifth embodiment of the invention is that by having a double-walledgarniture 511 and the cavity 512 therein, the steam is able to moreeffectively surround the garniture belt 113 and the filter rod 116therein as it passes through the garniture 511, which enables a quickerand more efficient heat transfer to the filter rod material, improvingthe process of setting the shape formed in the surface of the filter rod116. It is intended within the scope of the invention that the apparatusof the fifth embodiment of the invention may include a perforatedgarniture belt as described above, in order to further improve the heattransfer of the steam to the filter tow material and entrainedplasticiser.

A filter rod producing apparatus 610 of a sixth embodiment of theinvention is shown in FIG. 10, which is similar to the first embodimentshown in FIG. 2 and like features retain the same reference numerals.However, the apparatus 610 of the sixth embodiment of the inventionincludes a different configuration of the garniture 611. Morespecifically, the garniture 611 comprises heating elements 612 along itslength. In this embodiment, no inlet ducts are provided for theintroduction of steam into the garniture 611. Instead, the heat requiredto activate and accelerate the reaction of the plasticiser and thecellulose acetate of the filter material is provided directly byconduction from the heating element 612 through the wall of thegarniture 611.

An advantage of the apparatus 610 of the sixth embodiment of theinvention is that there is no requirement for any steam source toprovide the heat for the plasticiser/cellulose acetate reaction. It willalso be appreciated that as heat is transferred to the filter rodmaterial by conduction, it is not necessary to provide aperforated/porous garniture belt 113. However, for optimum effectivenessof the apparatus 610 of the sixth embodiment of the invention, thematerial of the garniture belt 113 should preferably be a good conductorof heat, such as a metallic material, so that a quicker and moreefficient heat transfer to the filter rod material can be achieved,improving the process of setting the shape formed in the surface of thefilter rod 116.

The heating element 612 may be provided on an outer surface of thegarniture 611, as shown in FIG. 10, or alternatively, may be formedintegrally within the walls of the garniture 611. The heating elementmay preferably be an electric heating element.

A filter rod producing apparatus 710 of a seventh embodiment of theinvention is shown in FIGS. 11 and 12, and is similar to the firstembodiment shown in FIG. 2, with like features retaining the samereference numerals. However, the apparatus 710 of the seventh embodimentof the invention includes a different configuration of the garniture711. More specifically, the garniture 711 comprises a pressure roller712 in the interior of the garniture 711 at an upper portion thereof.This is shown more clearly in FIG. 12 which is a cross-sectional viewalong the line Z-Z of FIG. 11. The pressure roller 712 is positioned andconfigured to guide the lateral edges of the garniture belt 113 togetheras the garniture belt 113 is deflected into the rolled up configurationto surround the filter rod 116 being formed therein. The pressure roller712 also serves to exert an inwards force on the garniture belt 113where the two lateral edges meet, corresponding to the seam of thefilter rod, in order to ensure the relief pattern is fully impressed onthe filter rod 116 all the way around its circumference and to avoid aless pronounced pattern being formed at the point at which the lateraledges of the garniture belt 113 meet. It is intended within the scope ofthe invention that one or more pressure rollers may be provided and maybe fixed within the garniture, or alternatively may be moveable andinwardly biased relative to the garniture passage. Furthermore, the oreach toilet 712 may be formed as part of the heater (or cooling) bar(not shown) which may be present at an upper portion of the garniture711, as described above.

A filter rod producing apparatus 810 of an eighth embodiment of theinvention is shown in FIGS. 13 and 14 and, similarly topreviously-described embodiments of the invention, is configured to formfilter rods from loose filter tow material which include a groovedrelief pattern formed on an outer surface thereof. The apparatus 810comprises a garniture 811 having a wide entrance 811 a and narrower exit811 b with a tapered ‘tow guide’ portion 811 c therebetween, and a guidefunnel 812 and transport jet, and a continuous garniture belt 813 whichextends through the garniture 811 and over a plurality of guide rollers814 and is driven to be conveyed around the rollers 114 in the directionshown by arrows ‘V’ in FIG. 13. As with the existing filter rodproducing apparatus 10, plug wrap ‘P’ may be fed from a spool 815 ontothe upper surface of the garniture belt 813 which conveys it through thegarniture 811 such that it deforms into a rolled up configurationsurrounding a compressed cellulose acetate filter rod, as describedpreviously.

The apparatus 810 of the eighth embodiment of the invention differs fromthe previously-described embodiments at least in that the garniture belt813 is not provided with any surface relief pattern to be impressed ontothe filter rod as the garniture belt 813 and filter tow material areconveyed through the garniture 811. Instead, the garniture belt 813 is athin continuous flexible belt of material. Furthermore, the inner wallof the garniture 811 is provided with a plurality of ribs 817 projectinginwardly and extending longitudinally towards the narrow exit opening811 b of the garniture 811. This can be seen more clearly in FIG. 14which is a cross-sectional view of the garniture 811 taken along theline W-W in FIG. 13.

In use, loose filter tow material (not shown), such as celluloseacetate, is fed into the funnel 812 as shown by arrow ‘E’ and is guidedinto the garniture 811 by a transport jet of compressed air from a jetnozzle (not shown). As the garniture belt 813 enters and is conveyedthrough the garniture 811, the filter tow material is compressed by theinwardly tapering section and the plug wrap P is folded around theoutside of the compressed cylinder of filter tow material, such that andwhen the filter tow material it exits though the narrow exit opening 811b of the garniture 811, the filter tow material is formed into acompressed cylindrical filter rod 816 enveloped by an outer plug wrap P.

As the filter tow material travels through the garniture 811, the ribs817 on inner surface of the garniture wall impress a grooved pattern onthe outer surface of the filter rod 816 so that when the filter rod 816exits though the narrow exit opening 811 b of the garniture 811, it hasa series of longitudinal grooves formed around its outer surface. Theribs are preferably provided only in the narrow portion of the garniture811 so that the grooves are only formed on the filter rod 816 once thefilter tow material is substantially fully compressed and circumscribedwith the plug wrap P. It will be appreciated that in this embodiment ofthe invention, the garniture belt 813 is sufficiently thin and flexiblethat the grooved shape can be effectively imparted onto the filter rod816 by the ribs 817 though the thickness of the garniture belt 813.

In order for the grooved pattern to remain set in the filter rod, thegarniture 811 includes a heating means which accelerates the reaction ofa plasticiser that is mixed with the cellulose acetate fibres to set thefibres in the desired shape. In the embodiment shown in FIG. 13, theheating means comprises inlet ducts 824 along the length of thegarniture 811 through which steam can be injected, as shown by arrows‘S’, as described previously in respect of the first embodiment of theinvention. Accordingly, as also described previously, in order that theheat of the steam can be most efficiently applied to the celluloseacetate and plasticiser mix, the garniture belt 813 may be porous toallow steam therethrough, for example, the material of the garniturebelt 813 itself may be porous, or the garniture belt 813 may includemeans to increase the porosity of the garniture belt, such asperforations. For example, the garniture belt may be formed from aperforated metal which is resiliently deformable to pass over therollers 814 and roll up within the garniture 811 and deform to the shapeof the interior wall of the garniture 811. Such a metallic perforatedgarniture belt would exhibit the advantages of being porous to allowsteam to pass therethrough, and also conductive to allow heat to beefficiently transferred from the heating means to the filter rod 816.

It is also intended within the scope of the invention that double wallstructure described above with reference to the fifth embodiment of theinvention, and the alternative heating means described above withreference to the sixth embodiment of the invention, could be applied tothe alternative garniture 811 of the apparatus 810 of the eighthembodiment of the invention.

In the first to seventh embodiments of the invention shown and describedabove, the garniture belts 113, 213, 313, 413, 513, 613, 713 includelongitudinal grooves formed thereon to impart a corresponding shape tothe outer surface of the resulting filter rod. However, the invention isnot intended to be limited to a method and apparatus for forming groovedfilter rods, and it is intended within the scope of the invention thatother shapes could be formed on filter rods by correspondingly shapedrelief patterns being formed on the garniture belts, such as helicalgrooved, circumferential grooves, discrete depressions or any othercombination/pattern of recesses/protrusions. Also, with regard toembodiments of the invention which include a garniture belt of connectedplates, not every plate of the garniture belt necessarily includes ashaped/grooved pattern thereon to impart a corresponding shape to thefilter rod. Instead, such a pattern could be provided on every otherplate only, or every third plate, or any other variation, such that thegrooved/shaped pattern is only imparted onto the resulting filter rodintermittently or in any desired spacing, as per the order of theshaped/non-shaped garniture belt plates. In such an embodiment, thoseplates which do not include a relief pattern thereon to impart a shapeto the filter rod may not necessarily be formed of the same material asthe shaped plates. For example, the sections of garniture belt betweenthe shaped plates may be of existing woven belt construction. Yetfurther, the plates of the garniture belt shown and described above areof metallic construction although they maybe of other suitable materialthat is sufficiently rigid to impart the shaped pattern on the filterrod within the garniture, but is also elastically deformable to be ableto roll up on itself to fit into the garniture. Such materials couldinclude plastic or rubber. However, metal plates, such as copper oraluminium, or even gold, provide the additional advantage of good heatconductivity to allow the heat from the steam or other heat source toquickly pass to the filter tow material and entrained plasticiser toeffect the shaping and setting of the filter rod. It is also intendedwithin the scope of the invention that the plates of the garniture beltmay be coated with a coating which may improve wear resistance and/or bea non-stick coating such as PTFE, titanium or a carbonised coating. Thelateral edges of the garniture belts of the invention are intended to atleast meet in the fully rolled up configuration with in the garniture,although they may also overlap in the most rolled up configuration,within the scope of the invention.

It is intended that the various embodiments of the invention describedabove may comprise a garniture belt formed of a single band with theintended relief pattern to be imparted on the filter rod, formed on thesurface thereof, instead of the garniture belt comprising a plurality orarticulated plates. Such a band could be made of sufficiently deformablematerial to enable it to pass over rollers of the apparatus, and deflectinto a rolled up configuration within the garniture, but also beresilient enough that the relief pattern thereon can be impressed intothe surface of the filter rod being formed. Such a garniture belt maypreferably be made of a conductive material such as metal, preferablyaluminium, to efficiently conduct heat from a heat means to the filterrod being formed. Furthermore, the garniture belt may includeperforations to enable steam in embodiments of the invention where steamis used as a heating source, of more effectively be transferred to thefilter rod being formed to transfer heat thereto.

All embodiments of the invention shown and described above include aplug wrap P being fed into the garniture and onto which the loose filtertow material is directed, such that the resulting filter rod 116comprises filter material wrapped in the plug wrap. However, it isintended within the scope of the invention that the plug wrap may beomitted and instead, the filter tow material may be fed directly ontothe garniture belt which conveys the filter material through thegarniture, compresses it into a filter rod and forms the desired reliefpattern on the outer surface thereof. In such an embodiment of theinvention, the filter rod produced would remain in the desired rod formwith the surface pattern thereon purely due to the compression exertedby the garniture belt within the garniture and the activation of theplasticiser entrained in the filter material. As a further alternativeintended to fall within the scope of the invention, a plug wrap-coatedfilter rod may be produced but instead of the plug wrap P beingintroduced together with the loose filter tow material into thegarniture, the filter rod with surface relief pattern may be formed inthe garniture without a plug wrap, as described above, and the plug wrapmay be subsequently wrapped around the formed filter rod once it hasexited the garniture. Such an embodiment is shown as an in dashed linesin FIG. 2 as an alternative configuration of the first embodiment of theinvention, in which a plug wrap P′ is fed from a spool 115′ and iswrapped around the filter rod 116 after it is has been formed in, andexited from, the garniture 111. The plug wrap P′ may be wrapped aroundthe filter rod such that the plug wrap P′ conforms to the relief patternformed on the surface of the filter rod 116, so that the finished filterrod with outer plug wrap P′ exhibits the desired surface relief patternon its outer surface. Although shown in FIG. 2 as an alternativeconfiguration of the apparatus of the first embodiment of the invention,it is intended that this alternative arrangement of plug wrapapplication could be used in any of the other embodiments of theinvention described above.

In the embodiments of the invention shown and described above whichinclude a garniture belt made of a plurality of articulated plates, therollers around which the garniture belt passes is described as beingfaceted to correspond to the individual plates of the garniture belt.However, the invention is not limited to such roller configuration andinstead, other rollers may be used, for example rollers with adeformable outer surface, such as rubber or plastic/polymer, to providea softer surface against which the garniture belt may lie and which maydeform to hold the shape of the garniture belt/plates. Alternatively,the rollers may include a plurality of recesses corresponding to theindividual plates of the garniture belt, and which receive eachgarniture belt plate as the garniture belt passes over the roller. Yetfurther, the rollers may be of an increased diameter so that thegarniture belt plates are less deformed on the large curved rollersurface.

Embodiments of the invention shown and described above are examples onlyand the invention is not intended to be limited to these specificexamples. Furthermore, it is intended that the present invention mayinclude any combination of non-mutually exclusive features describedabove, and is as defined by the scope of the claims hereafter.

1. An apparatus for manufacturing a filter rod for a cigarette or othersmoking article having a pattern formed in relief on the outer surfacethereof, the apparatus comprising: a passage including a portionconfigured to receive and compress filter material to form a filter rod;and a belt extending along the passage to convey filter material throughthe passage; wherein the apparatus includes a patterned relief surfaceconfigured to impress a relief pattern on a surface of a filter rod asit is formed within the passage.
 2. An apparatus according to claim 1wherein the relief surface is formed on the belt such that the beltengages the filter material and impresses the relief pattern on thesurface of the filter rod as it passes through the passage.
 3. Anapparatus according to claim 2 wherein the belt comprises a plurality ofplates hingedly coupled end-to-end.
 4. An apparatus according to claim 3wherein the front and rear edges of each plate which are hingedlycoupled to the adjacent plates, are formed with a correspondingtessellating and/or saw-tooth configuration.
 5. An apparatus accordingto claim 3 or claim 4 wherein the hinged connection between the platescomprises a flexible cord or a plurality of hinge pins.
 6. An apparatusaccording to any of claims 3-5 wherein the belt is driven over aplurality of guide rollers, wherein at least one of the guide rollershas a faceted outer surface and the belt is in registration with the atleast one guide roller such that the plates of the endless belt lie flaton a facet of the at least one guide roller as the belt passes over saidguide roller.
 7. An apparatus according to claim 2 wherein the beltcomprises a flexible band with a layer of resilient material formedthereon, the patterned relief surface being provided in the resilientmaterial layer.
 8. An apparatus according to claim 1 wherein the reliefsurface is formed on an inner surface of the passage such that thefilter material engages the relief surface of the passage and the reliefpattern is impressed into the surface of the filter rod as the filterrod passes through the passage.
 9. An apparatus according to anypreceding claim wherein the passage is configured to heat the filter towmaterial as is passes therethrough.
 10. An apparatus according to claim9 wherein the passage includes at least one inlet tube to allow steam tobe introduced into the interior of the passage to heat the filter towmaterial.
 11. An apparatus according to claim 9 or claim 10 wherein thepassage comprises a double wall structure along at least part of itslength, comprising an outer wall and an inner wall spaced from the outerwall to define a cavity therebetween.
 12. An apparatus according to anyof claims 9-11 wherein the passage includes at least one heating elementto heat the filter tow material within the passage, wherein the heatingelement(s) may comprise electrical heating element(s).
 13. An apparatusaccording to any preceding claim further comprising a pressing memberconfigured to impart an inward pressing force on the belt and/or filterrod as the filter rod is formed in the passage.
 14. A method ofmanufacturing a filter rod for a cigarette or other smoking articleusing a filter rod manufacturing apparatus as defined in any precedingclaim wherein the passage includes a first open end for introduction offilter material and a second open end for expulsion of a formed filterrod, the passage narrowing between the first end and the second end sothat as filter material is conveyed through the passage, it iscompressed to form a filter rod, the method comprising: feeding loosefilter tow material onto the belt; conveying the filter tow material onthe belt through the passage from the first open end to the second openend and thereby compressing the filter tow material to form a filterrod; and impressing a relief pattern on a surface of the filter rod asit passes through the passage.
 15. A method according to claim 14wherein the relief surface is formed on the belt, the method furthercomprising the relief pattern being impressed on the surface of thefilter rod by the patterned relief surface of the belt.
 16. An apparatusaccording to claim 15 wherein an inner surface of the passage includes arelief surface, the method further comprising the relief pattern beingimpressed on the surface of the filter rod by the patterned reliefsurface on the inner surface of the passage.